High salivary testosterone is linked to masculine male facial appearance in humans

Although many studies of male facial attractiveness assume that facial masculinity is related to circulating testosterone levels in adult males, there is little empirical evidence in support of this assumption. Here, we used salivary testosterone assays to investigate the relationship between circulating testosterone and both masculinity and attractiveness of facial appearance by (1) constructing digital composites from the faces of men with high and low testosterone, which were presented using a forced-choice task to subjects and (2) using a forced-choice task in which participants judged the masculinity of pairs of original photographs. Composites from high-testosterone men were judged to be more masculine than those from low-testosterone men. Evidence that high-testosterone composites are considered more attractive than low-testosterone composites was equivocal. The forced-choice task using the original face images indicated that participants identified faces associated with relatively high circulating testosterone as being more masculine than faces of men with lower circulating testosterone. This effect was more pronounced when the faces in the pair were from men who differed greatly in testosterone levels. These preliminary findings provide support for the underlying assumptions of much attractiveness research, particularly studies that have identified systematic variation in female preferences for masculine faces.